Toxicity of Checkpoint Inhibition in Advanced RCC: A Systematic Review

BACKGROUND: Checkpoint inhibitors (CPI) have now been established as standard agents in the management of patients with metastatic renal cell carcinoma (mRCC). Given the unique toxicity profiles of CPIs, a detailed understanding of their incidence rate and characteristics is critical. OBJECTIVE: To perform a systematic review for the analysis of the incidence rate and characteristics of toxicities in mRCC patients treated with CPIs in published clinical trials. METHODS: A systematic search of EMBASE (Ovid) and MEDLINE (Ovid) was conducted as per PRISMA guidelines to identify prospective clinical trials of checkpoint inhibitors in mRCC. The search method involved querying for the terms renal cell carcinoma or kidney carcinoma with any of the following: programmed cell death 1, PD-1, programmed cell death ligand 1, PD-L1, cytotoxic T-lymphocyte antigen 4, CTLA-4, immunotherapy, checkpoint inhibitor, anti-PD-1, or anti-PD-L1. Only prospective clinical trials were included. RESULTS: The systematic review yielded 9,722 records through the MEDLINE (Ovid) and EMBASE (Ovid) databases. Ultimately, five prospective clinical trials with 722 patients were selected for inclusion. The rates of any grade adverse event (AE) and grade (G) 3-4 AEs were 79.9% and 20.9%, respectively. Regarding immune-related AEs (irAEs), the most common system affected by any grade irAE was the skin (30.89%) and the most common grade 3-4 irAE was related to the hepatic system (8.23%). Rates of AEs were similar across the CPI monotherapy clinical trials. CONCLUSIONS: The rates of AEs in mRCC patients treated with CPI is similar to rates in other cancers. AEs in mRCC are fairly consistent among monotherapy trials with PD-1 and PD-L1 inhibitors and as one would expect higher when CTLA-4 and PD-1 inhibitors are offered in combination.